jbd2: clear revoked flag on buffers before a new transaction started

Currently, we clear revoked flag only when a block is reused.  However,
this can tigger a false journal error.  Consider a situation when a block
is used as a meta block and is deleted(revoked) in ordered mode, then the
block is allocated as a data block to a file.  At this moment, user changes
the file's journal mode from ordered to journaled and truncates the file.
The block will be considered re-revoked by journal because it has revoked
flag still pending from the last transaction and an assertion triggers.

We fix the problem by keeping the revoked status more uptodate - we clear
revoked flag when switching revoke tables to reflect there is no revoked
buffers in current transaction any more.

Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 6 insertions, 0 deletions

diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 68d704db787f..5069b8475150 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -430,6 +430,12 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 	jbd_debug(3, "JBD2: commit phase 1\n");
 
 	/*
+	 * Clear revoked flag to reflect there is no revoked buffers
+	 * in the next transaction which is going to be started.
+	 */
+	jbd2_clear_buffer_revoked_flags(journal);
+
+	/*
 	 * Switch to a new revoke table.
 	 */
 	jbd2_journal_switch_revoke_table(journal);